1. Field of the Invention
This invention relates to building ventilation and, more particularly, to a damper used in a wall of a building to control air movement through the building.
2. Description of the Related Art
In large buildings, such as agricultural or industrial buildings, there are often employed large electric fans to move air through the building. Louvers, shutters or dampers are installed in the walls of the buildings adjacent the large fans. The damper is open when the fan is on to allow air movement through the damper and closed when the fan is off, thereby preventing hot or cold exterior air from entering the building.
These conventional dampers are opened and closed by electric motors to coordinate with the on/off operation of the electric fans. Of course, the need for electric motors requires extra maintenance for the motor, extra cost for the motor and the electrical system for the motor, extra use of electricity to power the motor, etc.